The present technology relates to a liquid crystal display panel including a liquid crystal layer, and a liquid crystal display including the liquid crystal display panel. Moreover, the present technology relates to an electronic unit including the above-described liquid crystal display as a display section.
As liquid crystal displays have characteristics including a lighter weight, a smaller thickness, and lower power consumption, compared to CRTs (cathode-ray tubes), liquid crystal displays are used in many electronic units as displays. As classifications of liquid crystal displays in related art based on a method of applying an electric field to a liquid crystal layer, a vertical electric field mode and a horizontal electric field mode are known.
In vertical electric field mode liquid crystal displays, an electric field in a substantially vertical direction is applied to liquid crystal molecules by a pair of electrodes which are arranged with a liquid crystal layer in between. As the vertical electric field mode liquid crystal displays, TN (Twisted Nematic) mode liquid crystal displays, STN (Super Twisted Nematic) mode liquid crystal displays, VA (Vertical Alignment) mode liquid crystal displays, MVA (Multi-domain Vertical Alignment) mode liquid crystal displays, ECB (Electrically Controlled Birefringence) mode displays, and the like are known.
Moreover, in horizontal electric field mode liquid crystal displays, an electric field in a substantially horizontal direction (in an in-plane direction of a laminate plane) is applied to liquid crystal molecules by a pair of mutually insulated electrodes on an inner surface of one of a pair of substrates arranged with a liquid crystal layer in between. As the horizontal electric field mode liquid crystal displays, IPS (In-Plane Switching) mode liquid crystal displays in which a pair of electrodes do not overlap each other in a plan view and FFS (Fringe Field Switching) mode liquid crystal displays in which a pair of electrodes overlap each other in a plan view are known.
In these liquid crystal displays, the direction of a director aligned in a predetermined direction of the liquid crystal layer is changed by an electric field to adjust a light transmission amount, thereby displaying an image. An operation principle of such a liquid crystal display in related art will be described below referring to FIG. 22.
It is to be noted that a part (A) in FIG. 22 is a schematic sectional view of a vertical electric field mode liquid crystal display in related art. The liquid crystal display illustrated in the part (A) in FIG. 22 uses, as an optical device, a change in an optical phase difference caused by application of an external electric field (a voltage) to a liquid crystal layer. A part (B) in FIG. 22 is a diagram illustrating a light transmission state in the liquid crystal display illustrated in the part (A) in FIG. 22. Parts (C) and (D) in FIG. 22 illustrate examples of an alignment state of a director in a nematic liquid crystal layer having positive dielectric constant anisotropy. The part (C) in FIG. 22 illustrates an example of an alignment state of the director under no voltage application. The part (D) in FIG. 22 illustrates an example of an alignment state of the director under voltage application. Most of liquid crystal displays in related art perform display by changing alignment of a director of a liquid crystal such as a nematic liquid crystal at lower than a nematic-isotropic phase transition temperature (TNI).
As illustrated in the part (A) in FIG. 22, in a liquid crystal display 200 in related art, a liquid crystal layer 230 is sandwiched between an array substrate 210 and a color filter substrate 220. Transparent electrodes 240 and 250 are formed on surfaces located closer to the liquid crystal layer 230 of the array substrate 210 and the color filter substrate 220, respectively. Moreover, polarizing plates 260 and 270 are disposed on outer surfaces (surfaces located farther from the liquid crystal layer 230) of the array substrate 210 and the color filter substrate 220, respectively. As illustrated in the part (B) in FIG. 22, light incident from a backlight 280 to the polarizing plate 260 on the array substrate 210 is converted into linearly polarized light, and a phase difference is given to the linearly polarized light while the linearly polarized light passes through the liquid crystal layer 230. Only a component parallel to a transmission axis of the polarizing plate 270 on the color filter substrate 220 of the light provided with the phase difference passes through the polarizing plate 270, and light having passed through the polarizing plate 270 is visually perceived by a viewer (not illustrated).
For example, as illustrated in the part (C) in FIG. 22, when an electric field is not applied, the director in the liquid crystal layer 230 is aligned in a horizontal direction by actions of the alignment films 310 and 320 formed on the surfaces of the transparent electrodes 240 and 250, respectively. Moreover, for example, as illustrated in the part (D) in FIG. 22, when an electric field is applied, the director in the liquid crystal layer 230 is aligned in a vertical direction by an action of the electric field. As described above, the alignment state of the director in the liquid crystal layer 230 is changed with an electric field application state, thereby changing a phase of light passing through the liquid crystal layer 230. Therefore, in the liquid crystal display 200 in related art, the light transmission amount is adjusted by an interaction between the electric field generated by the pair of transparent electrodes 240 and 250 and a transmission axis of the polarizing plate 270, thereby displaying a predetermined image.
It is to be noted that the horizontal electric field mode liquid crystal display includes a pair of electrodes located closer to the array substrate; however, the horizontal electric field mode liquid crystal display is in common with the above-described vertical electric field mode liquid crystal display in that the light transmission amount is adjusted by an interaction between an electric field generated by the pair of electrodes and a transmission axis of a light-emission side polarizing plate, thereby displaying a predetermined image.